ieee1394: eth1394: handle tlabel exhaustion
When eth1394 was unable to acquire a transaction label, it just dropped
outgoing packets without attempt to resend them later.
The transmit queue is now halted if no tlabel is available to
->hard_start_xmit(). A workqueue job is then scheduled to catch the
moment when ieee1394 recycled the next lot of tlabels.
Fixes http://bugzilla.kernel.org/show_bug.cgi?id=8402
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/ieee1394/eth1394.c b/drivers/ieee1394/eth1394.c
index 8e4c959..d6b19c2 100644
--- a/drivers/ieee1394/eth1394.c
+++ b/drivers/ieee1394/eth1394.c
@@ -47,6 +47,7 @@
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/init.h>
+#include <linux/workqueue.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
@@ -235,6 +236,9 @@
/* This is called after an "ifdown" */
static int ether1394_stop(struct net_device *dev)
{
+ /* flush priv->wake */
+ flush_scheduled_work();
+
netif_stop_queue(dev);
return 0;
}
@@ -531,6 +535,37 @@
}
/*
+ * Wake the queue up after commonly encountered transmit failure conditions are
+ * hopefully over. Currently only tlabel exhaustion is accounted for.
+ */
+static void ether1394_wake_queue(struct work_struct *work)
+{
+ struct eth1394_priv *priv;
+ struct hpsb_packet *packet;
+
+ priv = container_of(work, struct eth1394_priv, wake);
+ packet = hpsb_alloc_packet(0);
+
+ /* This is really bad, but unjam the queue anyway. */
+ if (!packet)
+ goto out;
+
+ packet->host = priv->host;
+ packet->node_id = priv->wake_node;
+ /*
+ * A transaction label is all we really want. If we get one, it almost
+ * always means we can get a lot more because the ieee1394 core recycled
+ * a whole batch of tlabels, at last.
+ */
+ if (hpsb_get_tlabel(packet) == 0)
+ hpsb_free_tlabel(packet);
+
+ hpsb_free_packet(packet);
+out:
+ netif_wake_queue(priv->wake_dev);
+}
+
+/*
* This function is called every time a card is found. It is generally called
* when the module is installed. This is where we add all of our ethernet
* devices. One for each host.
@@ -574,6 +609,8 @@
spin_lock_init(&priv->lock);
priv->host = host;
priv->local_fifo = fifo_addr;
+ INIT_WORK(&priv->wake, ether1394_wake_queue);
+ priv->wake_dev = dev;
hi = hpsb_create_hostinfo(ð1394_highlevel, host, sizeof(*hi));
if (hi == NULL) {
@@ -1390,22 +1427,17 @@
u64 addr, void *data, int tx_len)
{
p->node_id = node;
- p->data = NULL;
+
+ if (hpsb_get_tlabel(p))
+ return -EAGAIN;
p->tcode = TCODE_WRITEB;
- p->header[1] = host->node_id << 16 | addr >> 32;
- p->header[2] = addr & 0xffffffff;
-
p->header_size = 16;
p->expect_response = 1;
-
- if (hpsb_get_tlabel(p)) {
- ETH1394_PRINT_G(KERN_ERR, "Out of tlabels\n");
- return -1;
- }
p->header[0] =
p->node_id << 16 | p->tlabel << 10 | 1 << 8 | TCODE_WRITEB << 4;
-
+ p->header[1] = host->node_id << 16 | addr >> 32;
+ p->header[2] = addr & 0xffffffff;
p->header[3] = tx_len << 16;
p->data_size = (tx_len + 3) & ~3;
p->data = data;
@@ -1451,7 +1483,7 @@
packet = ether1394_alloc_common_packet(priv->host);
if (!packet)
- return -1;
+ return -ENOMEM;
if (ptask->tx_type == ETH1394_GASP) {
int length = tx_len + 2 * sizeof(quadlet_t);
@@ -1462,7 +1494,7 @@
ptask->addr, ptask->skb->data,
tx_len)) {
hpsb_free_packet(packet);
- return -1;
+ return -EAGAIN;
}
ptask->packet = packet;
@@ -1471,7 +1503,7 @@
if (hpsb_send_packet(packet) < 0) {
ether1394_free_packet(packet);
- return -1;
+ return -EIO;
}
return 0;
@@ -1514,13 +1546,18 @@
ptask->outstanding_pkts--;
if (ptask->outstanding_pkts > 0 && !fail) {
- int tx_len;
+ int tx_len, err;
/* Add the encapsulation header to the fragment */
tx_len = ether1394_encapsulate(ptask->skb, ptask->max_payload,
&ptask->hdr);
- if (ether1394_send_packet(ptask, tx_len))
+ err = ether1394_send_packet(ptask, tx_len);
+ if (err) {
+ if (err == -EAGAIN)
+ ETH1394_PRINT_G(KERN_ERR, "Out of tlabels\n");
+
ether1394_dg_complete(ptask, 1);
+ }
} else {
ether1394_dg_complete(ptask, fail);
}
@@ -1633,8 +1670,17 @@
/* Add the encapsulation header to the fragment */
tx_len = ether1394_encapsulate(skb, max_payload, &ptask->hdr);
dev->trans_start = jiffies;
- if (ether1394_send_packet(ptask, tx_len))
- goto fail;
+ if (ether1394_send_packet(ptask, tx_len)) {
+ if (dest_node == (LOCAL_BUS | ALL_NODES))
+ goto fail;
+
+ /* Most failures of ether1394_send_packet are recoverable. */
+ netif_stop_queue(dev);
+ priv->wake_node = dest_node;
+ schedule_work(&priv->wake);
+ kmem_cache_free(packet_task_cache, ptask);
+ return NETDEV_TX_BUSY;
+ }
return NETDEV_TX_OK;
fail: